Board Thread:Pokémon Help/@comment-31658174-20170513013953/@comment-28826236-20170513020505

For your Diancie, I suggest changing the nature to one that doesn't lower Special Attack (it mainly focuses on that). I know Ancient Power has a chance to raise stats and stuff, but it has a really low PP. I think the Move Reminder in the Battle Colusseum can help it learn Power Gem, which has a higher base power and more PP.

For Victini.....honestly, IDK what the nature should be, but since you seem to be focusing more on Special Attack, I'd say try a Mild nature. Other than that, it's OK, but I would suggest pairing it up with your Mega Charizard Y in Double Battles.

For Lopunny, Hardy is good enough, but I suggest you changing it to an Adamant nature (as far as I know, they focus mainly on their Attack stat). You can keep Thunderbolt for now, until the Wild Charge TM comes out.

For Greninja....well, Jolly has the potential to be a pretty good nature for it, if you focus on Attack more. Change Dark Pulse to Night Slash, maybe?

For Lucario, you can change its nature to either Adamant or Modest, depending on what stat you choose to focus on. IDK, replace Bone Rush with Earthquake? And to cover Ghost-types (if needed), change Rock Climb to Shadow Ball.

Lastly, Quirky is okay for Charizard, but I'd suggest a Hasty nature for it. Since Overheat has a really low PP and will lower Charizard's Special Attack after usage, you probably can replace it with Flamethrower. Everything else is perfectly okay.

I don't really have much in the way of items, so I'm just gonna say they're fine. This is just my suggestion, you don't have to take it seriously. :)